Machines, such as dozers, excavators, and drill machines, are controlled to perform various earth moving operations in a worksite. Generally, a positioning system is used for determining a location of the machine in the worksite. The positioning system combines GPS/GNSS information with inertial measurement unit (IMU) information to determine a position and orientation of the machine in the worksite. The GPS/GNSS information is generally received at various modes including RTK fixed mode, RTK float mode, Differential mode and Autonomous mode, and each of such modes is associated with an error. If the positioning system uses a high quality GPS/GNSS mode, such as the RTK Fixed mode and switch over to a lower quality GPS/GNSS mode, such as the Autonomous mode, then the GPS/GNSS signals received at the Autonomous mode can cause an offset error more quickly than if the positioning system uses the IMU to dead reckon. Hence, the positioning system may determine a location of the machine different from actual location of the machine in the worksite.
U.S. Pat. No. 8,872,700 (the '700 patent) discloses a GNSS surveying receiver with multiple RTK engines. The position of a global navigation satellite system (GNSS) surveying receiver is determined based on a plurality of RTK engines. A first RTK engine is implemented using a first set of parameters. A second RTK engine is implemented using a second set of parameter different than the first set. A plurality of GNSS signals are received from multiple satellites. At least one correction signal is received from at least one base receiver. A first position is determined from the first RTK engine based on the GNSS signals and the at least one correction signal. A second position is determined from the first RTK engine based on the GNSS signals and the at least one correction signal. A final position of the GNSS surveying receiver is determined based on the first position or the second position or a combination of both positions. The '700 patent does not disclose a positioning system that may be fused with an IMU to determine a location of the machine in an worksite based on error estimate associated with signals received from the satellites.